Anti-kickback device

ABSTRACT

An anti-kickback device is disclosed where the device includes a plurality of flexible members, and at least a compliant contact surface in contact with a moving workpiece, where the flexible members provide a biasing force against the workpiece and also resist or prevent kickback of the workpiece as it engages a tool such as a shaper, saw blade, etc. The configuration of the flexible members assures an opposing force to resist kickback.

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 15/073,864 for an ANTI-KICKBACK DEVICE, filed Mar.18, 2016 by D. Keith Bow, which also claims priority from U.S.Provisional Patent Application No. 62/134,812 for a FEATHERBOARD WITHLIVING HINGES, filed Mar. 18, 2015 by Ronald and Keith Bow, and fromU.S. Provisional Patent Application No. 62/182,783 for a FEATHERBOARDWITH FRICTION-INCREASING MATERIAL, filed Jun. 22, 2015 by Ronald andKeith Bow, all of which are hereby incorporated by reference in theirentirety.

The disclosed embodiments generally relate to a device having thecapability of biasing a workpiece against a work surface such as a fenceor table and limiting the potential for the workpiece to move in thedirection of the cutting tool. Specifically, an accessory apparatus usedfor guiding a workpiece into a blade or similar cutting tool andresisting any kick-back of the workpiece while it is being worked on. Inone embodiment, the apparatus includes a plurality of curved membersattached to a body via a living hinge.

BACKGROUND AND SUMMARY

Anti-kickback devices are known to be used with a work table or similarwork surface, such as a table saw or shaper, to safely guide a workpiecealong the table as it is processed by a cutting implement, such as a sawblade, shaper or other tool bit. Typically featherboards are mounted on,or attached to, a worktable, a guide fence or both, and adjusted to adesired position to accommodate the width (and possibly the height) ofthe stock to be cut. However, a feather board may be severely limited inthe amount of sideward pressure that can be applied, while stillallowing the workpiece to be fed between the feather board and the guidefence. Such practical limitations also limit the amount of resistancethat can be exerted on the workpiece. Accordingly, there exists a needfor an anti-kickback device capable of easy set up yet providing agreater opposing force while at the same time maintaining a manageableinfeed pressure.

The anti-kickback device embodiments disclosed herein serve to apply abiasing force to the workpiece in order to assure that the workpiece isdirected to the tool and that chatter is reduced in the workpiece, aswell as provide a safety feature by opposing kickback (reverse feed)forces generated by the cutting tool that tend to thrust the workpiecetowards the operator.

In the disclosed embodiments, the anti-kickback device includes aplurality of flexible members designed to extend at an angle to contactand guide at least one surface of the workpiece in a manner such that asthe work piece is fed by and in contact with the anti-kickbackdevice(s). As will be appreciated, the anti-kickback device may beconfigured to contact a workpiece in various positions (e.g., workpiecebetween the device and a fence, workpiece between the device and atable, etc.) In operation the flexible members are deflected slightly bycontact with the workpiece, and as a result exert a force or pressurethat encourages the workpiece to remain in alignment with the fence ortable as the workpiece passes a tool such as the blade. The tips of theflexible members, formed of a deformable material such as a rigid foam,also partially conform to the surface of the workpiece to assurefrictional contact. In the various embodiments described herein, theflexible members extend from a body that is further attached to asupport frame or central structure of the device. Because the flexiblemembers are angled in the direction of workpiece movement, should thecutting tool catch the work piece and try to “kick” it rearward, theflexible members self-lock in opposition to the rearward motion of theworkpiece.

In one embodiment of the anti-kickback device, the flexible members movein an arcuate manner in response to the rearward movement of theworkpiece to strongly oppose rearward motion and the workpiece becomesbound between the device and the fence. In actual practice the membersalso maintain the workpiece in parallel alignment with the saw blade andguide fence so as to mitigate the potential for jamming of the workpieceand subsequently kicking it back at the operator. As noted above, afurther attribute of the disclosed flexible member design is that thecompliant material that the base and flexible members are made ofcreates a living hinge and the flexible members and base further absorbvibrations thereby also decreasing or eliminating chatter of theworkpiece and assuring a smooth cut edge of the workpiece.

Disclosed in embodiments herein are anti-kickback devices for use with awork surface, comprising: a body and a plurality of flexible membersextending from at least one side of the body, each of said flexiblemembers connected to the body by a living hinge; and at least onemechanism associated with the anti-kickback support frame for adjustablyattaching the device to a work surface relative to the workpiece, aswell as an adjustment mechanism suitable for securing the device againstmovement relative to the work surface.

Further disclosed in embodiments herein is an anti-kickback device,comprising: a body and a plurality of compressible flexible membersextending from at least one side of the body, wherein the outer shape ofeach of the plurality of flexible members includes a generally planarsurface extending from a first radiused recess adjacent the body, anarcuate surface, terminating at one end thereof in a line intersectingthe planar surface, a second radiused recess at an opposite end of thearcuate surface, the second radiused recess having a slot extendingtherefrom, and a living hinge portion, connecting the flexible member tothe body, the living hinge being located between an end of the slot andthe first radiused recess; and a mechanism associated with the body forreleasably attaching the anti-kickback device to a stationary worksurface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D are illustrations of the various profiles associated withone of anti-kickback flexible members as a function of operationalforces;

FIG. 2 is an illustrative example of the anti-kickback flexible membersmounted within a support frame, absent a workpiece;

FIG. 3 is an illustrative example of the anti-kickback device flexiblemembers mounted within a support frame in forcible contact with aworkpiece;

FIG. 4 is an illustrative example of the anti-kickback flexible membersmounted within a support frame in an anti-kickback reactive mode;

FIGS. 5-10 are representative illustrations of an embodiment of theanti-kickback device having flexible members only attached to a base,absent a support frame;

FIGS. 11-15 are representative illustrations of an embodiment of theanti-kickback device with a support frame that provides for removal andreplacement of the flexible member body;

FIG. 16 illustrates two anti-kickback devices used in combination in avertical and horizontal arrangement;

FIGS. 17A and 17B provide exploded views of two anti-kickback devices ina stacked configuration, respectively with and without spacers betweenthe devices;

FIGS. 18-21 are illustrations of alternative embodiments of theanti-kickback device;

FIGS. 22 and 23 are illustrations of two alternative devices used inaccordance with a band saw embodiment;

FIG. 24 is an illustration of a kick-back device depicting an embodimentproviding replacement body pieces, each having alternative fingerconfigurations; and

FIGS. 25-28 are illustrations of alternative configurations for theanti-kickback device.

The various embodiments described and depicted herein are not intendedto limit the disclosure to those embodiments described. On the contrary,the intent is to cover all alternatives, modifications, and equivalentsas may be included within the spirit and scope of the variousembodiments and equivalents set forth. For a general understanding,reference is made to the drawings. In the drawings, like references havebeen used throughout to designate identical or similar elements. It isalso noted that the drawings may not have been drawn to scale and thatcertain regions may have been purposely drawn disproportionately so thatthe features and aspects could be properly depicted.

DETAILED DESCRIPTION

Referring now to the figures, FIGS. 5, 11 and 18-23 illustrate variousembodiments of the anti-kickback device. In all cases, however, thedevice employs a plurality of flexible members or “fingers” that extendfrom a body or base, and the tips of which remain in conformable contactwith at least one surface of a workpiece. For example, depicted in FIG.1A is a first embodiment of a flexible member 120, in a relaxed orneutral position. Flexible member 120 includes an area having a minimumcross section dimension “T”, shown as 142, which provides for aresilient hinge point having a center of rotation 148, as shown in FIG.1C. Living hinge 124 is as a flex point that comprises a thin bendableregion made from the same material as the flexible member and base. Thematerial preferably provides for minimal friction and nominal wear, aswell as flexibility to enable the living hinge.

Absent any contact with a workpiece the distal point of flexible member120 is located an offset angle theta (θ) from the Y axis of hinge 124.However, when considering the device in use against a workpiece,flexible member 120 is rotated a radial distance theta (θ) clockwiseabout the centroid 148 of living hinge 124 as seen in FIG. 1B, and byvirtue of the offset radius is compressed by a rearward force exerted bythe workpiece as it is kicked back.

The living hinge portion 124 comprises, for each member, a reducedcross-section of the material from which body 114 and flexible member120 are constructed from. In other words, the cross-sectional area ofmaterial connecting the flexible member to the body in living hingeregion 124, in this embodiment, is smaller than a cross section of otherparts of the flexible member. A nose or limiter 131 serves to limit theangular displacement of flexible member 120. This applied pressurethrough the adjustable mounting of the support frame 134 compresses thedistal end region 129 of flexible member 120, as depicted in FIG. 1C andFIG. 3, which in turn increases the contact surface area 144, whileproviding a compressive static force against the workpiece. Accordingly,flexible member 120 is positioned to react to a rearward motion of theworkpiece by resisting the kickback force, whereby the workpiece isessentially jammed between guide fence 425 and the anti-kickback device100. As illustrated in FIG. 1D, in combination with FIG. 4, flexiblemember 120, by virtue of rotating clockwise about the offset radius ofliving hinge 124, takes on a column like configuration as it is furthercompressed under clockwise rotation initiated by the rearward-movingworkpiece. This now semi-rigid member 120 provides a relatively stiffconnection between the workpiece and the device applies a considerablecounter force that is greater than the reactive kickback force.

Turning next to FIGS. 2-4, a plurality of flexible members 120 arearranged into a row, each being attached to a common body 122 by livinghinges 124. Flexible member body 132 is removably inserted withinsupport frame 134 to accommodate a variety of flexible member/livinghinge profiles to permit varying degrees of kickback control, allow forreplacement of worn components, etc. As will be appreciated, differentconfigurations of the flexible members and the material they are madefrom and/or coated with results in each having its own respectiveresilience, and performance characteristics. As noted, flexible memberbody 132 is also replaceable when worn out or damaged. As an example ofan embodiment with a support frame and alternative replacement,reference is made to FIG. 24.

FIGS. 2-4 depict several operative states of anti-kickback device 100,(i) standby, (ii) engaged and (iii) reactive kickback mode. In FIG. 3,support frame 134 and flexible members 120 have been positioned againstworkpiece 427 so as to cause flexible members 120 to provide a nominallateral force by displacing their distal end and rotating living hinge124 up to limiter 131. Workpiece 427 is subsequently fed into blade 421taking the path of least resistance as the flexible members yield to theforward motion. However, in FIG. 4 a reactive force generated by theblade becoming jammed within the cut, causes the workpiece to engageflexible members 120 in a rearward direction, thereby engaging them inan upright semi-rigid state to stop or dampen the kickback, and in sodoing protecting the operator from serious injury. In effect, flexiblemembers 120 collectively provide a one-way feed path, or ratchet, for aworkpiece being feed into a blade across a work table.

As seen in FIGS. 5-9 an alternative embodiment of anti-kickback device100 employs support frame 134 by placing cutout 130 directly within body122. As shown in FIG. 5, an exemplary embodiment of anti-kickback device110 includes a flexible member body 122, a clamping arrangementcomprising insert 128, backing plate 138, treaded/tapered member 214,threaded/slotted slide bar 210 and knob 136. In an alternativeembodiment, clamping members such as cam-shaped levers and alternativehardware (e.g., threaded holes, T-slot channels) may be employed toreleasably attach the devices to work surfaces.

Also considering the embodiment of FIGS. 5-7 the anti-kickback device110 includes a plurality of flexible members 120 attached to the body122 via living hinge 124 formed of the same materials as the member andbody. In one embodiment an ethylene vinyl acetate (EVA) foam is used forthe body and members of the anti-kickback device, whereas the insert 128is formed of a more rigid material such as a molded plastic or formedmetal. It will be appreciated that alternative foams, such asurethane-based compositions or other materials, may be employed for thebody, the flexible members or any coatings thereon. The intent is thatthe material from which the body and fingers are formed is able toprovide a rigid, although flexible and conformable contact with aworkpiece, and preferably does not mar or damage the workpiece.

In the embodiments of FIGS. 5-10 an elongated cutout region 130 withinthe anti-kickback device 110 is of a size and shape to receiving asimilarly shaped rigid liner 128, where the rigid liner is of a size andconfiguration suitable for fitting within cutout 130 and receiving afastener in order to form an adjustment mechanism to secure theanti-kickback device to a work surface.

Also illustrated in FIGS. 5, 7 and 8 depict alternative components thatmay be employed as part of or with the anti-kickback device 110 lockingand attachment mechanism. Specifically, magnetic switches 190 areintended to be used as an alternative to the slide bar, bolt and knobcombination and may be placed directly into the opposite ends of thecentral slot of insert 128, and upon activation the magnets will firmlyhold the insert and associated flexible member assembly 132 in most anyposition on the work surface, independent of a slot. The switches aresold by MagSwitch in various configurations (e.g., MagFixture 150).Accordingly, the adjustment mechanism, in the alternative embodiments ofFIGS. 5, 7-9 and 11-13, includes a knob, or hand-actuated cam lockingmechanism, (not shown) within the body to removably attach theanti-kickback device to the work surface and/or fence.

Referring briefly to FIG. 8, a similar alternative embodiment for theanti-kickback device 110 is illustrated, where the body 120 has aplurality of flexible members or teeth, and where magnetic lockingdevices are inserted having frictional contact with holes in the bodyand extend through the body such that the locking devices are able toestablish a magnetic contact with a work surface and hold theanti-kickback device 110 in place most anywhere along the work surface,independent of channel 423

Referring to FIG. 9, anti-kickback device 110, in accordance with thedisclosed embodiments, is illustrated in use on a conventional tablesaw. The device assembly is generally indicated at 110 attached to awork surface or table 413. The work surface is depicted as a table of atable saw, including a table 415 having a surface 417, an opening 419 inthe table permits a rotating tool such as a saw blade 421 to extendthrough the opening. A channel 423 in the table, which may be aninverted T-shaped channel, permits the insertion and locking of toolsand components such as the anti-kickback device 110. Fence 425 ispositioned on the surface 417 of the table 415. In an alternativeconfiguration, the anti-kickback device 110 may also be attached tofence 425, which has a similar channel 429 extending along the length ofthe fence. The channel 429 receives the corresponding locking slide ofthe anti-kickback device 100 or 110 apparatus in a manner similar tochannel 423. In particular, as indicated in FIG. 7, the locking andadjustment mechanism may include one or more rectangular slide bars 210,held in place by a force created via a threaded bolt 214 having aconical shaft in combination with a knob, or similar internally threadedmember 136 suitable for drawing the screw and slide bar towardanti-kickback device 110 and backing plate 138, thereby causing theslide bar to expand and be in frictional contact with the shoulders ofchannel 423 and/or channel 429.

In combination, the anti-kickback device 110 and fence 425 operate toguide workpiece 427 being pushed by an operator into blade 421 so thatthe stock is cut or modified as it is moved across surface 417. It willbe appreciated that device 110 can be used with other work surfaces 417such as shaper tables without altering the scope of the disclosedembodiments.

Referring now to FIG. 10, depicted therein is a close-up view of theflexible member profile of the anti-kickback device 110 in contact witha workpiece 427. More specifically, when living hinge 124 is in a flexedposition, caused by arcuate surface 236 being in contact with workpiece427, the slot 242 and adjacent recesses 230 and 244, form an ellipticalshaped opening 260 between the living hinge portions of adjacent members(teeth). It should be noted that when a kick back force is exerted onworkpiece 425 slot 242 closes down and limits the displacement of theflexible member as surface 240 comes in contact with the body. Each ofthe plurality of flexible members 120 is of a shape comprising agenerally planar surface 232 extending from a first radiused recess 230adjacent body 122. The member then transitions at tip 234 to an arcuatesurface 236 where the line of intersection of surfaces defines thedistal tip of member 120. Arcuate surface 236 terminates at the oppositeend along an abrupt corner 238, which is formed along a lineintersecting a planar surface 240 of slot 242. A second radiused recess244 is found at the opposite end of the slot, and the space between thesecond radiused recess and the first radiused recess defines a livinghinge portion 124 that connects the tooth to the body. In particular,the living hinge portion 124 comprises, for each member or tooth, areduced cross-section of the material than that from which the body andteeth are made.

Considering now the second exemplary embodiments illustrated in FIGS.11-15, the interconnecting region of device 100 includes one or morecomplementary interlocking features 610 extending from at least one sideother than the flexible member side. The interlocking features 610 onthe body provide mating features that dovetail with contrasting featureson support frame 650. Accordingly, support frame 650 of theanti-kickback device 100 includes mating feature(s) that interlock withcontrasting features on body 122. The insert may be further secured inplace using a suitable adhesive or may remain in a frictional, but yetremovable fit.

In the depicted embodiment of FIGS. 11-13 and 24, the adjustment andmounting mechanism 620 includes a molded plastic or metal support frame650 having not only mating features (610, 652), but also one or moreadjustment slots 660 through which a threaded bolt 214 may pass in orderto provide the ability to attach the anti-kickback device 100 to a worksurface in the manner previously disclosed above relative to the firstembodiment in FIGS. 5-10. As illustrated in the alternative bodyembodiment of FIG. 24, for example, body (122 a, 122 b) may have theflexible members 120 connected in different or alternativeconfigurations for the living hinge region 124, thereby allowing for notonly the substitution and replacement of the body, but where alternativehinge region designs facilitate variations in the “sensitivity” of theanti-kickback device. As another alternative, the ability to replace thebody 122 further permits the shaping of the ends or tips of the flexiblemembers to improve contacts with workpieces that have a shaped orirregular profile (e.g., moldings). In such a configuration, theconforming EVA foam material, along with a pre-shaped surface, wouldassure appropriate contact between the flexible members and the worksurface and would improve resistance to kickback of shaped work surfaces(e.g., post-shaping).

Both FIGS. 14 and 15 further illustrate the features of a plurality offlexible members 120 essentially connected to body 122 via a livinghinge 124. As previously discussed the profile of the flexible member,in combination with a specific material, provides for a significantlyimproved reactive force in response to the kick back energy of aworkpiece.

Referring next to FIG. 16 at least two anti-kickback devices 100 or 110are engaged to afford a combination of both a horizontal and verticalforce to further avert the potential for a kickback occurrence.Furthermore, workpiece chatter is significantly subsided by providing acontinuous damping force onto the workpiece 427 by the flexible membersof one or more devices 100. In particular when the workpiece issufficiently thin, only a portion of flexible member 120 is compressedwhereby the remaining area has a tendency to overlay the upper surfaceof the workpiece, which further serves to stabilize the workpiece. Alsocontemplated is an embodiment where in a combination of devices 100, thedifferent devices are formed with fingers having differentcharacteristics (e.g., flexible hinges of different strengths) so as toprovide “heavy” or “light” resistance to an advancing workpiece. In thestackable configuration (FIGS. 17A, 17B) or when mounted to differentwork surfaces as depicted in FIG. 16 (tables, fences, etc.), thecombination of anti-kickback devices can reliably bias the workpiece andresist kickback.

As best shown in FIGS. 17A and 17B two or more anti-kickback devices areessentially stacked one onto another to increase the vertical workingheight and thereby provide additional surface area to accommodate a workpiece having a thickness greater than the height of a single device.Spacers 170 are inserted between a pair of devices 100 and secured oneto another via extended mounting bolt 172, and optionally by pins orsimilar protrusions intended to interlock with features of the supportframes for each device. In the alternative, two or more devices can bedirectly stacked on top of one another as seen in FIG. 17B, having amounting bolt 174 of sufficient length to accommodate the additional twoor more device(s).

Further disclosed in embodiments herein is an improvement to atraditional feather board as illustrated in FIGS. 18-21. In embodimentssimilar to those disclosed above, the modified devices are intended foruse on a work surface and in a similar manner to the embodiments aboveeach includes a plurality of flexible members such as fingers 36extending angularly therefrom. However, the fingers are formed from orinclude a conformable, friction-increasing material 60 thereon.

Referring to FIG. 18, depicted therein is a feather board 102, which isadapted to be mounted to work table 417 of a table saw. While describedrelative to a saw table, it will be appreciated that the anti-kickbackdevice such as feather board 102 may also be employed with otherwoodworking devices such as joiners, shapers and the like. The worksurface, such as saw table 417, includes channel 423 which extendslongitudinally across the table and parallel to blade 421. The table sawalso includes a rip fence 425 that is secured to the saw table by clampsor similar devices.

The feather board 102 includes a body having transverse slots formounting to the saw table. Body 28 includes a plurality of angularlyextending, flexible fingers 36, protruding from the longitudinal portion30 between the sides having adjustment slot 34. The fingers 36preferably make an angle with the longitudinal portion of less than 90°.Feather board 102 includes an expansion bar, as previously discussed,which is positioned beneath the body and sets within groove 423 on thesaw table 427. As further illustrated in FIGS. 19 and 20, feather board102 includes a plurality of parallel elongated flexible fingers 36extending angularly from body 28, where in region 60 the fingers mayhave an associated friction-increasing and/or compliant materialapplied. Flexible fingers 36 may, in one embodiment, be encapsulated atthe tips with a silicone-based material. For example, the silicone-basedmaterial may include an expandable silicone covering or tubing material70 that is stretched and applied over at least the ends of some or allof the fingers. The covering may extend the entire length of the fingersor may be applied just adjacent the tips of the fingers 36. Moreover, itis further contemplated that the covering may be replaceable or moveableso as to permit such a covering to be adjusted or replaced in the eventthat it is worn away or damaged.

Considering FIG. 20, depicted therein is an illustration of an exemplaryset of fingers 36 from a feather board, wherein the tips identified asregion 60, of at least some of the fingers 36, have been treated with ordipped in a rubber compound 80. In other words, at least the ends of thefingers that are in contact with a workpiece are coated or dipped in therubber compound. And further considering FIG. 21, the feather board 102is further illustrated as including a friction-increasing material suchas an EVA filler 90 applied between, and possibly extending slightlybeyond the tips of fingers 36. It will be appreciated that the filler 90may be affixed to the fingers or near the base using a suitableadhesive. As illustrated, the filler may not need to be applied betweeneach set of adjacent fingers, but may be interspersed betweenevery-other pair of fingers, for example.

Also contemplated is the use of one or more of the embodimentsillustrated, for example, in FIGS. 19-21 in combination with the otherembodiments related to work-contacting devices to facilitate increasingthe friction force, particularly in relation to preventing kickback of aworkpiece.

As an alternative embodiment, reference is made to FIGS. 20 25-28, inwhich alternative configurations of the elongated flexible elements aredepicted. For example, the anti-kickback device of FIGS. 19-20 may haveelongated flexible members 36 formed from a rigid foam material asdisclosed previously, where the elongated members could have a contactsurface 420 (e.g., a tip, cover, end) made of a compliant or conformablematerial such as EVA or other type of foam or a pliable or rubberizedmaterial. As illustrated in FIG. 25, the first end of each flexiblemember consists essentially of a rigid, albeit flexible, material andthe second end (region 418) of each flexible member consists essentiallyof a deformable material such as EVA foam. In this way the elongatedmembers may have a relatively thin or narrow cross-section that permitsflexibility, but at the contact surface on the second end the membersare each able to contact and conform to the surface(s) of a workpiece.More specifically, the first end of each flexible member may consistessentially of a resilient, non-deformable material such as cast ormachined metals, hard plastics or polymers (e.g., acrylonitrilebutadiene styrene (ABS, UL94V), polyvinyl chloride (PVC),polyetheretherketone (PEEK), etc.) that are injection-moldable and/ormachinable, and wood, bamboo and similar plant-based materials.

In yet another embodiment, the anti-kickback device is not limited to aparticular configuration and it will be appreciated that any manner ofconnecting and supporting a plurality of elongated flexible members tobe in contact with a workpiece may be employed. In such configurations,it is once again the characteristics of the elongated members thatfacilitate the biasing force and anti-kickback features. For example,each of said flexible members has a first end operatively connected to asupport, and a second end in contact with the workpiece, wherein atleast a portion of the second end of each flexible member includes amaterial that remains in conformable contact with at least one surfaceof the workpiece to apply a biasing force to the workpiece. Moreover,for workpieces that may be of irregular or pre-formed shapes having aplurality of different surfaces the second end of each flexible memberremains in conformable contact with at least two adjacent surfaces ofthe workpiece.

As a further alternative embodiment depicted in FIGS. 26-28, theanti-kickback device 510 may include a roller(s) 518 on the end of oneor more of the elongated members 512. For example, the roller may beformed of a rigid cylindrical core 520 (e.g. machined metal or aninjection-molded polymer) with a deformable material on at least anouter surface 524 thereof in order to create an enlarged contact region(surface of the roller conforming to workpiece as it moved by) ratherthan simply a line of contact. Also contemplated is some form of ratchetpawl 530 and detents or recesses 532 about the interior of the core, ora similar mechanism, used to attach the roller at its axis (pivot) 534so that each roller turns in only one direction—the direction in whichthe workpiece is intended to move for processing. As illustrated in thealternative roller embodiment of FIG. 28, contact with the workpiece maybe further enhanced by the use of a flexible belt 540 that runs over andaround several the rollers 518.

In summary, the embodiments disclosed herein illustrate an anti-kickbackdevice including a body and a plurality of flexible members extendingfrom at least one side of the body wherein the outer shape of each ofthe plurality of flexible members (teeth) includes a generally planarsurface extending from a first radiused recess adjacent the body, anarcuate surface, terminating at both ends thereof in a line intersectinga planar surface. A second radiused recess having a slot extendingtherefrom, and a living hinge portion spanning the distance between thefirst and second radiused recesses connects the tooth to the body, theliving hinge being a living hinge and preferably formed from the samematerial as the teeth and body. The body is attached to or furtherincludes a releasable adjustment mechanism for releasably attaching theanti-kickback device to a stationary surface such as a work table.

Briefly referring to FIGS. 22 and 23, depicted therein are alternativeconfigurations of the disclosed device, where the flexible members ofeach embodiment are not employed so much for anti-kickback but toprovide a biasing force against a fence or similar structure. Theadvantage of such embodiments is that the device can be position so asto apply the biasing force near the blade—at a position that would beunsafe for a user's hands. In both embodiments, one or more rows offlexible members 2210 or 2310 are in contact with the workpiece and dueto the flexible nature and separation of the members, they both deflectas well as conform to the surface of the workpiece as it is beingadvanced toward a blade 2250 such as on a band saw. As will beappreciated from a review of the flexible members in FIG. 22, themembers are formed from the base material and are cut to produce one ormore parallel rows of flexible members.

Experimental and Comparative Testing

The following experiment(s) were conducted to evaluate the performanceof the anti-kickback device tooth design disclosed herein, in particularthe amount of opposing force that the teeth provide to resist kickback.While the tooth design of FIG. 14 was used for testing purposes, itshould be understood that a similar design having approximately sixteeth, as illustrated in the figure, would be expected to have similarresults under the same testing conditions.

Experiment 1: a table saw configuration as generally illustrated in FIG.10 was used with an anti-kickback device. Specifically, theanti-kickback device embodiment illustrated in FIG. 16 was employed andplaced in contact with an edge of the workpiece. The workpiece was thenpulled in the direction opposite the normal sawing direction using adigital scale to measure and record the maximum force applied before theworkpiece started to slip relative to the anti-kickback device 100. Themeasured force applied to the workpiece was over 96 lbs. when theworkpiece started to slip backward against the anti-kickback device.

To provide a contrasting measurement, a feather board by Mag-Tools (30mm), including approximately thirteen angled “feathers” in contact withthe workpiece was tested in a similar manner. The reverse pulling forceneeded to cause the same workpiece to slip against the feather board wasless than approx. 15 lbs. Accordingly, it appears that the design of theflexible members in accordance with the disclosed embodiments produces agreater resistance to movement of the workpiece than conventionalfeatherboards.

Experiment 2: In a similar configuration to FIG. 16, a workpiece wasplaced into position against the table saw fence and was once againengaged by the respective anti-kickback device 100. The table saw bladewas set to a depth where if would not cut through the workpiece, but, asadvanced a cut would be placed in approximately one-half the workpiecethickness. This configuration was believed to provide the worst-caseloading of the blade without adding additional force above the height ofthe anti-kickback device.

When a workpiece was engaged by the anti-kickback device, the workpiececould be advanced into contact with the saw blade and no kick-backoccurred. In one trial, the workpiece was raised above the sawblade andforced down onto the blade to be cut, and no kick-back occurred.

When a workpiece engaged by the competitive feather board was advanced,to be cut by the blade, the workpiece was released by the operator andthe workpiece was kicked back by the saw blade.

In conclusion, based upon the experiments conducted, it appears that thedesign and materials of the disclosed embodiment provide a level ofresistance to the kick-back of a workpiece in contact with the ends ofthe flexible members that of conventional feather board device employinga series of parallel “feathers”.

It should be understood that various changes and modifications to theembodiments described herein will be apparent to those skilled in theart. Such changes and modifications can be made without departing fromthe spirit and scope of the present disclosure and without diminishingits intended advantages. It is therefore anticipated that all suchchanges and modifications be covered by the instant application.

What is claimed is:
 1. An anti-kickback device for biasing a workpieceon a machine having a work surface that guides the workpiece relative toa tool, said anti-kickback device comprising: a support frame having atleast one slot therein for adjustable attachment relative to the worksurface; and a plurality of elongated flexible members having a firstend operatively connected to the support frame, and a free moving secondend opposite the first end, said second end being suitable for slidingcontact with the workpiece, wherein at least a portion of the second endof each flexible member comprises a deformable material and thedeformable material is conformable to a non-planar workpiece surface inorder to assure contact between said second end and the workpiecesurface; where the second end of each of the plurality of elongatedflexible members remain in conformable contact with said workpiece andprovide a biasing force against the surface of the workpiece.
 2. Theanti-kickback device according to claim 1 wherein the flexible membersremain in frictional contact with said workpiece and further provide acounter-reactive force in response to kickback of the workpiece.
 3. Theanti-kickback device according to claim 1 further including anadjustable expansion member placed within a channel of the work surfaceto attach the support frame to the work surface.
 4. The anti-kickbackdevice according to claim 1 wherein said frame is attached to the worksurface using a magnetic force.
 5. The anti-kickback device according toclaim 1, wherein each of said elongated flexible members are formed froma compliant material.
 6. The anti-kickback device according to claim 5,wherein the compliant material further includes a rubber compound, andwhere at least the ends of said flexible members are coated with therubber compound.
 7. The anti-kickback device of claim 1 furthercomprising an adjustment mechanism associated with the support frame forattaching, adjusting and securing the support frame relative to the worksurface.
 8. The anti-kickback device according to claim 1, wherein eachof said elongated flexible members are formed from a foam material. 9.The anti-kickback device according to claim 1 wherein the first end ofeach flexible member consists essentially of a rigid material and thesecond end of each flexible member consists essentially of a deformablematerial.
 10. The anti-kickback device according to claim 1 wherein thefirst end of each flexible member consists essentially of a resilient,non-deformable material.
 11. An anti-kickback device for applying abiasing force on a workpiece, said anti-kickback device comprising: aplurality of elongated flexible members, each of said flexible membershaving a first end operatively connected to a support, and a second endin contact with the workpiece, where the elongated flexible membersdeflect along their length in response to contact with the workpiece,and at least a portion of the second end of each of the plurality ofelongated flexible member includes a material that deforms to conform toa non-planar shape of the workpiece and thereby remains in conformablecontact with at least one surface of the workpiece to apply a biasingforce to the workpiece.
 12. The anti-kickback device according to claim11, wherein the second end of each flexible member remains inconformable contact with at least two adjacent surfaces of theworkpiece.
 13. The anti-kickback device according to claim 11, whereinthe second end of each flexible member includes a roller.
 14. Ananti-kickback device for applying a biasing force on a workpiece, saidanti-kickback device comprising: a plurality of elongated flexiblemembers, each of said flexible members having a first end operativelyconnected to a support, and a second end in contact with the workpiece,wherein at least a portion of the second end of each of the plurality ofelongated flexible member includes a material that remains inconformable contact with at least one surface of the workpiece to applya biasing force to the workpiece, wherein the second end of eachflexible member includes a roller and each roller includes a deformablematerial on at least an outer surface thereof.
 15. The anti-kickbackdevice according to claim 13, wherein each roller turns in only onedirection.
 16. The anti-kickback device according to claim 11, whereinthe material that remains in conformable contact with at least onesurface of the workpiece includes a belt riding over the surface of aplurality of rollers, at least one of said rollers being constrained toturn in only one direction.